PFAS
PFOS
Perfluorooctanesulfonic acid — a long-chain sulfonated PFAS compound.
What is PFOS?
PFOS is a perfluorinated sulfonic acid that was widely used in surface treatments and firefighting foams before restrictions were introduced.
Why test for it?
Like PFOA, PFOS is commonly reported as an individual parameter because of its persistence and the level of scientific attention it receives.
Where can it come from?
- Aqueous film-forming foams used historically
- Surface and textile treatments
- Industrial legacy sites
How is it measured?
Determined by LC-MS/MS with isotope dilution, reported in ng/L per compound with method-specific detection limits.
What does my result mean?
PFOS is often reported together with PFOA and other target PFAS so the overall profile, not a single number, informs the conclusion.